An O(n log n)-Time Algorithm for the Restricted Scaffold Assignment.

The assignment problem takes as input two finite point sets S and T
and establishes a correspondence between points in S and points in T ,
such that each point in S maps to exactly one point in T , and each point
in T maps to at least one point in S. In this paper we show that this
problem has an O(n log n)-time solution, provided that the points in S
and T are restricted to lie on a line (linear time, if S and T are presorted).